<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>

</body>
</html>
<script>
    var txt = 12345;
    console.log(typeof (txt+""));
    console.log(typeof String(txt))
    console.log(typeof txt.toString());
    var num = 10;
    console.log(num.toString(2));  //  1010

</script>